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SIDNEY G. THOMAS, OF 3 QUEENS ROAD VILLAS, COUNTY OF',SURREY,

ENGLAND.

BASIC PROCESS OF TREATING IRON IN THE MANUFACTURE 0F BESSEMER STEEL.

SPECIFICATION forming part of Letters Patent No. 253,130, dated January 31, 1882.

Application filed November 8, 1879. Patented in England September 3, 1879, in Belgium October 15, 1879, and in France I December 5, 1679.

To all whom 1.15 may concern.

Be it known that I, SIDNEY GrLoi-inis'r THOMAS, of 3 Queens Road Villas, in the county of Surrey, England, have invented a certain Improvement in the Basic Process of Treating Iron in theManufacture of Bessemer Steel, which process is fully described in the following specification.

In carrying out my process for.the manufacture of Bessemer steel from phosphoretio pigiron, as described in my Patent No. 217,495, dated July 15, 1879, in a basic-lined vessel, with a calcareous slag and an al'ter-blow, I have found that instead of adding to the dephosphorized and decarburized metal spiegeleisen or form-manganese in the ordinary way, a greatly improved result in the economy of manganese, thered notion of the tndencyot' the spiegel to put back the phosphorus from the into slag the steel, and freedom from red-shortness is obtained by proceeding as follows: To the decarburized and dephosphorized metal, at the termination of the after-blow, I add from three to seven per cent. of molten pure pig-iron containing preferably less than .10 per cent. (one-tenth) of phosphorus and sulphur, and at least one per cent. of silicon and less than three per cent. thereof. I then immediately after add to the metal sufiicient rich spiegel or ferro-manganese to give the desired amount of manganese and carbon to the steel. I find for hardrail-steel six or seven per cent.

of pure pig-iron containing about two percent. of silicon, followed by five per cent. of spiegel, with fifteen to seventeen per cent. of manganese, is a good proportion. The spiegeleisen or ferro-manganese should also be molten, or, in the ease of ferro-manganese, redhot lumps may sometimes be used. By this means I deoxidize the metal by the carbon and silicon of the pure pig-iron without wasting manganese, thus effecting a notable economy of manganese, and I also reduce the tendency of the spiegel to put back phosphorus from the slag into the steel, and I produce ahigher quality of steel, entirely free from any tendency to red-shortness. This addition of pigiron is only advantageous when using a calcareous slag and lining and an after-blow, as before described by m It is at present the practice to recarburi-ze Bessemer refined metal made by the ordinary or acid process by adding to it a certain quantity of spiegeleisen or of term-manganese. It has also been proposed to add to refined Bessemer metal a mixture of pure pig-iron and metallic manganese, and it has been proposed to add, in general terms, the additions which are necessary for manganese, and, if wished, also carbon and silicium.

It has further been proposed, in order to make sound castings from ordinarythat is, undephosphorized-Bessemer or Siemens steel, to add silicon to the metal, either by means of an addition of a special highly-silicious pig iron, containing from five to ten per cent. of silicon, followed by term-manganese, or by an addition of aspecial compound of silicon, mauganese, and iron, known as silico-ferro-manganese. This addition is specially directed to be made, and has always been madein such proportions as to leave from one-tenth to siX- tenths of SlllCOIl in the steel, and, as I have before observed, the addition is always made either as a special compound of silicon, manganese, and iron, or a special highly-siliconized pig-iron-that is, a special pig-iron containing over five per cent. of silicon-the object always being to leave one-tenth per cent., or more, of silicon in the steela thing which is, for my purpose, highly prejudicial.

Now, none of these methods, if applied to dephosphorized metal, answers the purpose I have in vie\v-namely, the prevention ot'rephosphorization, the saving of manganese and iron, and the giving a very high quality of metal, eminently suited for rolling and forging without red-shortness; and I do not claim any of these processes, nor do I claim the use of silico ferro-manganese, or of a pig-iron containing over five per cent. of silicon, as an addition; but

What I claim as new, and constituting the subject of my present invention, is-

The herein-described improvement in the process of treating iron, whichconsists in addizing' it, withoutwasting manganese, and with- 10 out leaving so much as one-tenth per cent. of silicon in the metal, substantially in the manner and proportions herein described.

SIDNEY GITICHRIS'I THOMAS.

Witnesses:

PHILIP S. J USTIGE, ALLEN P. JONES. 

